Planning the congestion charge zone.  A visualisation showing traffic flows, speeds and accidents would help with the decision making.

Sadly, governments rarely engage citizens in policy co-creation in Eastern Europe.

I have heard of a collaboration with the State Government in Nigeria and a public university to create a link bridge that eased traffic situation which had affected the state for a long time. Adding visualisation would help to assist users on their choice of routes 

In Lithuania there is no such thing as policy co-creation 

As I am from Belgium, I now know about the co-innovation example in Mechelen.

The campaign "Stadtradeln" in Germany urges users (here cyclists) to download an app to track their covered distances for a three week period. It is a competition between municipalities in Germany and a fun activity. however, at the same time, the app collects data in the background and this data is then forwarded to the participating cities as a data base for improving their cycling infrastructure.

As far as I know there isn't a co-creation transport policy in Croatia.

In Belgium, there is the TMaaS Project: https://soc.kuleuven.be/mintlab/blog/project/tmaas/ 

A few years ago Knokke-Heist started a platform to receive the ideas from the citizens. This platform isn't used any more because there is no good visualization of the location where they want improvement.

https://knokke-heist.citizenlab.co/nl-BE

I think a visualisation components could improve co-creation. However, we should always expect people to have a minimum of experience in interpreting graphs before they should be able to have a say in anything. 
Making things easy accessible is a good thing, but i can (and probably will) be misused because of not enough experience with statistics or just to push an agenda.

Traffic counters data portal - UK

I know about the co-innovation example from this course in Mechelen.

I think that the visualisation component is important as it makes the outcome of the data analysis more accessible to all parties who may be interested in the issue but lack skills to understand the data otherwise. However, it is important that the visualisation is done correctly, because, as we have seen, different visualisation can lead to different conclusions being made. 

An example of partial co-creation is the design process for the Sustainable Urban Mobility Plan in L'Aquila:

www.pumslaquila.it

Visualization instruments could be improved.

we have had covid policies closing off roads to create pedestrainised zones that allow safe distancing, which were co-created with advisement from public health authorities. there was a visualisation component on the newtwork system to show closures and diversions so we could see which areas were made covid safe,